1. Field of the Invention
The present invention pertains generally to electrical power supplies and, particularly, to protection circuitry which provides delayed disabling of a power supply and signaling of impending such disabling upon detection of overvoltage or undervoltage power supply output. 2. Discussion of the Related Art: Industrial power supplies are used to provide electrical power to a variety of devices which include digital logic circuitry. Many times a multitude of small power output power supplies are arranged in a distributed power architecture fashion such that each power supply supplies a small amount of power to specific circuits or circuit boards. This distributed power architecture contrasts with a power supply arrangement wherein several larger power supplies are used to provide electrical power to all circuits over several power busses. However, such small power output power supplies generally do not incorporate any type of fault analysis circuitry for detection of out of range or out of specification power supply output voltage, i.e., overvoltage or undervoltage. When overvoltage or undervoltage output is supplied by a power supply, logic circuit results are unreliable because the results of logic operations are unpredictable and many times erroneous. Additionally, valuable information may be lost when a power supply output exceeds prescribed limits, producing such unreliable results, and steps are not taken to preserve such information pending shutdown of the power supply.